1. Field of the Invention
The present invention relates to a technology for collecting waste toner in an image forming apparatus.
2. Description of the Related Art
Replacement of consumables or maintenance of image forming apparatuses, which used to be performed by a service staff, are performed by the users of the apparatuses these days. This is because the image forming apparatuses have been made smaller than ever before. As a result, the number of components used in the image forming apparatuses have been minimized, and the users are forced to replace components having a relatively short useful life, such as a waste-toner container, by themselves at regular intervals. The waste-toner container is used to accumulate transfer residual toner, paper dust, and the like. If one would like to get rid of the need to replace the waste-toner container, then it will be necessary to mount a sufficiently large waste-toner container that could accommodate amounts of waste toner and the like for the entire life of the image forming apparatus, which results in an increase in the overall size of the apparatus undesirably.
Image forming apparatuses capable of reusing waste toner have been developed. Such image forming apparatuses are advantageous in that reuse of the waste toner results in saving of resources. However, this type of image forming apparatuses are relatively bulkier for various reasons. For example, it is necessary to provide a waste-toner collecting path in the apparatus. Moreover, the waste toner is contaminated by paper dust generated from transfer paper, so that to collect the waste toner properly, it is necessary to provide a screw for conveying the waste toner, a component for collecting the waste toner smoothly, and the like. Therefore, there has been expected to develop a waste-toner container having a longer useful life while reducing the number of components to prevent the apparatus from growing in size.
For example, Japanese Patent Application Laid-open No. H11-327397 discloses a technique for collecting waste toner in a waste-toner container. Specifically, an image forming apparatus disclosed in Japanese Patent Application Laid-open No. H11-327397 includes an image carrier; a cleaning unit that cleans a surface of the image carrier; a cleaner case in which waste toner collected by the cleaning unit is conveyed; a waste-toner conveying screw that conveys the waste toner; and a striking member that applies an impact force to the cleaner case or the waste-toner conveying screw. The striking member is configured to apply an impact force to the cleaner case or the waste-toner conveying screw while any toner image is not formed on the image carrier. In accordance with rotation of the waste-toner conveying screw, an elastic protrusion formed on the striking member has pulse-contact with the waste-toner conveying screw, whereby the waste-toner conveying screw receives a vibration. Therefore, it is possible to prevent toner from accumulating at a location where the toner is relatively prone to accumulate, for example, a gap between a tip portion of the waste-toner conveying screw in a conveying direction and a wall of a waste-toner collecting device. Consequently, it is possible to prevent occurrence of a conveying error of the waste toner.
However, even with the use of the above technique, the image forming apparatus cannot be sufficiently downsized because of the need to provide the striking member. Furthermore, it is not preferable to apply an impact force to the component. In most cases the image forming apparatus is installed near a personal computer, so that it is necessary that the image forming apparatus be less noisy so as not to annoy the user of the personal computer.